1. Field
The present disclosure relates to inner focus lens systems, interchangeable lens apparatuses and camera systems.
2. Description of Related Art
Interchangeable lens apparatuses, camera systems, and the like, each including an image sensor for performing photoelectric conversion, are strongly required to realize size reduction and performance improvement. Various kinds of lens systems used in such interchangeable lens apparatuses and camera systems have been proposed.
Japanese Laid-Open Patent Publication No. 2011-076022 discloses a rear focus type inner focus lens having a shortened back focal length, which is composed of, in order from the object side, a first lens unit having positive refractive power, and a second lens unit having positive refractive power.
Japanese Laid-Open Patent Publication No. 2011-064919 discloses an inner focus lens which is composed of, in order from the object side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having positive refractive power, and a fourth lens unit having negative refractive power. In the inner focus lens, focusing is performed by the second lens unit and the third lens unit.